How to create text box

I’m using Twine 2.3.14 and SugarCube 2.34.1. I’m completely teaching myself CSS and HTML and am struggling a lot with this one thing, so was hoping someone would be able to help me. I want to create this box that my text sits in, like in the image attached in this link -

If anyone can tell me what the code is I would really appreciate it. I’ve looked on Google and everything I’ve tried isn’t working!

Twine Version: 2.3.14
Story Format: SugarCube 2.34.1

Answered in your “Wrapping text in a white box” Reddit thread.